


Babysitting a Sunbeam

by TheDarkestDandelion



Series: The Daemon, the Soldier and a Stolen Bio-Weapon AU [25]
Category: Final Fantasy XV
Genre: Alternate Universe - Canon Divergence, Ardyn Being Ardyn, Baby Prompto Argentum, Babysitting, Brotherly Love, Date Night, Fluff, Lies, Multi, Near Accidents, Paranoia, Parent Ardyn Izunia, Parent Cor Leonis, Prompto Argentum is a Ray of Sunshine, Sibling Rivalry, Surprises, Trust Issues, Whining, cuteness
Language: English
Status: Completed
Published: 2019-06-16
Updated: 2019-06-16
Packaged: 2020-05-12 15:00:56
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,690
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19231486
Author URL: https://archiveofourown.org/users/TheDarkestDandelion/pseuds/TheDarkestDandelion
Summary: Cor and Ardyn decide to go out for the first time since they adopted Prompto. Now, they need to find someone to look after their little sunbeam. Unfortunately for Ardyn, Cor is only going to allow one person to look after Prom and that person is Somnus.What could possibly go wrong?





	Babysitting a Sunbeam

**Author's Note:**

> Can't enough of this family. It is just adorable.
> 
> Hope you enjoy :)
> 
> Edited: So I realised I made another error in this story, to do with the timeline. Oh well, all fixed now. Sorry about that.

“Pleasseeeee….”

Ardyn pleaded, kneeling on the floor holding onto Cor’s leg, shaking it to get his attention.

The Marshal crossed his arms looking down at Ardyn. The man had been acting like a child all day and kept asking him the same question. And Cor would give him the same answer: no. But instead of listening, Ardyn decided to act more childish than their 2-year-old son. Unlike Cor who was getting very annoyed because Ardyn wouldn’t stop whinging, Prompto was happily entertaining himself ignoring his father’s. He was sitting a couple of feet away from his parents playing with a few stuffed toys and happily giggling to himself.

Cor rolled his eyes in annoyance, it became apparent that Ardyn needed more attention then Prompto did.

“If you are so desperate to go out, go out with someone else.”

“But I want to go out with you.” Ardyn whined, kissing Cor on the knee.

“Yeah, and who is going to look after this little one.” Prompto turned to his parents and started to laugh. However, Cor was not laughing. He glanced over to his son and notice that he had something colourful in his mouth. He had never stood up so quick in his entire life. Cor practically ran over to Prompto and picked him up, and because Prompto was laughing it was easy for him to get the item off of him. “Prompto, unless it’s food or drink, don’t put things in your mouth.”

Cor got the thing off of Prom, only to discover it was a bit of cardboard from a jigsaw puzzle that the boy had broken a couple of days ago. He told Ardyn to vacuum this morning. If Cor wasn’t so relieved that Prom hadn’t gotten a hold of anything dangerous, he would definitely be shouting at Ardyn by now.     

“Daddy, I want it back.” Prompto said trying to reach the soggy piece of cardboard.

“Don’t think so mate.”

Cor put Prompto back down on the floor and ignored him when he started to whine and sat back down on the sofa. Realising his dad was not going to return the item to him, Prom pouted and went back to playing with his Chocobo doll and Cattus.

Ardyn snorted at his son’s reaction and when Cor was sitting back down, he lent his head against his leg and went back to moaning at him.

“But it will be nice, we could always hire a babysitter. As much as I love our darling sunbeam of a son, we haven’t really had a moment to ourselves.”

Cor let out a sigh of defeat. “Alright, if it will stop you from whining we can go out later.”

“Yeye! I love you.”

“But… I get to decide who babysits him.”

“Deal.” Ardyn smiled lifting his head up in triumph.

“You’re going to regret saying that. I choose Somnus.”

“NO!”

“Then we’re not going anywhere.” Cor shrugged his shoulder’s leaning back into the sofa.

Cor found Ardyn’s reaction hilarious. His face had turned into a sulk and he moved away from Cor, acting like he had betrayed him. Cor didn’t want to go out because he didn’t want to leave Prompto with anyone that wasn’t him or Ardyn. They had adopted Prompto six months ago and Cor still didn’t trust the council not to pull a fast one on them. The council didn’t like Prompto’s presents and they hated the fact that he was already close friends with Noctis. If it meant using Somnus as an excuse not to go out and stay here so he could protect his son, he would.

A high-pitched giggle filled the room followed by Prompto waddling towards his dads. Ardyn held his arms out and smiled at the boy. “Sunbeam come here.”

“Dyn-Dyn!”

Prompto laughed as he fell into Ardyn’s arms and buried his face into his chest. However, the scarf’s tickled his nose forcing him to sneeze loudly. Ardyn sat the child on his lap and bounced him on his knee, ruffling his golden hair as Prompto continued to giggle. “Bless you, my dear. My Marshal, as much as I ‘care’ for my baby brother he is not looking after Prompto by himself. Ever.”

Ardyn did not trust Somnus. He knew that Somnus would never intentionally hurt Prom in any way shape or form, but he hated it when Cor and his brother sparred together. He hated it when Somnus was near anyone that he remotely cared about. It was because of what happened to Aera, and even if that was a long time, Ardyn just hated it. It was completely down to paranoia and he was happy to admit that. He did not like the idea of Somnus being in charge of his son. No. It wasn’t happening. 

“Come on Ardyn, Somnus would love to babysit him.” Cor said gesturing to Prompto, who had somehow got a hold of Ardyn’s hat without Ardyn complaining.

“I don’t care.”

“Ardyn? Has Somnus even been round to see Prompto?”

“Of course, he has.”

“No. Have you, off your own back, without me being present, ever invited your brother over to see _his_ nephew?”

“No.”

Cor shook his head. This everlasting feud was getting ridiculous now. Cor had spoken to both Ardyn and Somnus about it, and neither of them seemed like they were willing to try and mend it. There were odd occasions when the pair forced themselves to put everything behind them and work together, and to Cor this was one of these times. It wasn’t fair to deprive Somnus of seeing Prom, nor was it fair for Prompto not to have his uncle in his life.

Cor spoke plainly and calmly. All of this was probably because Ardyn was feeling petty. “Somnus lets you near Noctis, and you two are meant to bash each other’s brains out.”

“I know. I am being petty on purpose.”

He knew it. He fucking knew it.

“That’s it. We are going out tonight, and Somnus is babysitting. Don’t start whining, because of your reasoning, you no longer get a say in this.”

Cor got his phone out of his pocket, much to Ardyn’s dismay, and rang Somnus straight away. 

* * *

 

Cor was the one who went to answer the door and before he left the living room, he turned to Ardyn and pointed at him aggressively.

“Be nice.”

“I am always nice.”

 _Yeah right?_ Cor thought to himself as he exited the room. He really hoped that Somnus would babysit Prom and the brothers didn’t start fighting again. Cor hadn’t exactly asked Somnus to babysit Prompto yet, he just invited the Founder King around to see his nephew. The main reason being that Cor wanted Ardyn to ask Somnus. That way they may start to get along better, and Cor wouldn’t have to push for it anymore. He was fed up with it there constant bickering.

“Good evening Somnus.” Cor greeted the man, letting him in his house.

“Evening.”

The two went back into the living room to find Ardyn sitting on the floor with Prompto sitting in front of him, facing Ardyn. Ardyn looked at his son sternly and took some blocks out of his hat that Prom had placed in it. He began stacking them, whilst making sure that Prompto was watching what he was doing.  

“Sunbeam, the blocks do not go in Dada’s hat. They are to be stack like this.”

“No, in hat.” Prom said taking the blocks off the stack and returning them to the hat.

“No. Stacked.”

“No, in Dyn’s hat.”

Ardyn let out a deep sigh. “Are you ever going to call me ‘dada?’”

“Already back chatting you, I see.” Somnus commented crossing his arms over his chest.

“Hello, Som.” Ardyn rolled his eyes, clearly annoyed at his brother’s presence, removing the blocks from his hat again.

Prompto’s little face lite up hearing his uncle’s voice and he turned around and started clapping at Somnus. He began to giggle and smile brightly at the man and started to crawl his way over to him. Ardyn did not understand why Prompto loved Somnus so much, and he hated it. It was of course because he was jealous, however, Prompto was in the room and he was not about to start an argument with Somnus when his son was present. Instead, he remained on the floor and watch carefully as Prom made his way to Somnus.

“Om! Om!”

“Hello, buddy.” Somnus let go a small smile at the boy’s reaction.

Cor noticed, remaining behind his brother in law, Ardyn’s scowl. He could tell that Ardyn was very uncomfortable with this, but it was his own fault for being a petty git. Cor trusted Somnus with his son, Ardyn just needed to grow up and do the same. The Marshal got Somnus’s attention and began to explain the reason why he invited him over.   

“Somnus, before you and Ardyn have an argument, we would like to ask a favour of you. We would like to go out tonight, and we were wondering if you would babysit for us?”

“Call it an olive branch, brother dear.” Ardyn put on a fake smile as he stood up, swiping his hat off of the carpet.

Somnus knew for a fact that Ardyn had been pushed into it and he didn’t have a chance to make a comment on that as he was forced to look down at the floor. Prompto had latched himself to his leg and pulled himself up, giggling up at his uncle. It was cute. Somnus didn’t do cute. But he hadn’t seen Prompto in a couple of weeks now, and this was probably the only chance he was going to get, to spend with his nephew. Ardyn didn’t seem happy about this advancement, and because of that Somnus doubted this opportunity would ever arise again.

“I would love too.” Somnus nodded, thanking Cor.

“Here you are then.” Ardyn picked up Prompto and carefully place the boy in his brother’s arms. In the flash of pink, he handed Somnus a piece of paper as well. “Be good for uncle Om, Sunbeam. Daddy and I are going out for a bit and we will be back later. Prompto, that’s my hat.”

Prompto had taken the hat out of his dad’s hands and started hugging it as if he was attempting to hide it. “My hat!”

“Let him have it, or we are never going to leave. Thank you, Somnus. **We** really appreciate this, don’t we Ardyn?” Cor said giving Ardyn an opportunity to thank his brother.

He didn’t. Instead, he kissed Prompto on the forehead and walked passed the pair and headed for the living room door, ignoring Cor and leaving his fedora in his son’s care. Cor wanted to strangle him sometimes. Why couldn’t he just be fucking nice?

Cor thanked Somnus again before saying goodbye to Prompto and leaving the house before the boy started to give him puppy dog eyes. He still really didn’t want to leave Prom but if they didn’t do it now, there was no telling when Ardyn and Cor would.

After the front door closed, Somnus placed Prompto back on the carpet and read whatever Ardyn had handed to him. And in bold letter’s it read:

**I will make the rest of our immortal life hell if my son is harmed in any way under your care.**

** Understood. **

**Have fun XD!**

Somnus gulped. Over the years Ardyn’s abilities and threats started to cause him less discomfort as he had grown used to them. Sometimes, however, Ardyn still had the ability to scare the shit out of him. That note sent shivers down his spine because he knew Ardyn was not joking. Maybe he shouldn’t have agreed to babysit Prompto. Somnus didn’t really like children and they didn’t really like him all too much either. He hardly spent any time with Noctis and when Regis, Mors or any of his grandchildren were children he kept his distance. Ardyn was mainly the fault of that. He was the fun loveable uncle that all of his grandchildren seemed to be in awe of. But as they got older they realised that Ardyn was basically a child himself and would mess everything up if he found it amusing, even at the expense of others. All of them would then get on better with Somnus. But he was stuck with Prompto now, he might as well try to get on with him. 

He carefully sat down and looked at the blonde boy, who had started biting Ardyn’s hat. His brother was not going to be happy when he found that out, but it was funny. Unable to hide the amusement, Somnus chuckled. “So buddy, what do you want to do?”

“Bloks.” Prompto smiled crawling back over to the blocks with Ardyn’s hat still firmly gripped in his hands.

“Okay.”

* * *

 

There was a reason Somnus didn’t like children. That was because they were quick. They were there one minute and gone the next and it scared Somnus, and because of Ardyn’s warning, the Founder King had to be even more alert then he would be with Noctis if he was in charge of him. And during the evening there may have been a few incidences where Ardyn’s vow may have had to be enforced.

All Somnus did was take his eyes off the boy for a second and the child nearly poured burning hot tea all over himself.

He placed the tea on the coffee table, glanced over to the left of him to see Prom playing with a toy car, then turn to his right to get himself a biscuit and when he went to pick up his tea, Prompto was directly in front of him reaching out for the cup. Somnus jolted forward, grabbed Prom and placed him back over to the left of him. Before Prom could go back to his goal, Somnus picked up the cup and ensured it was not in his nephew’s reach again.

“Prompto. We do not touch this. It’s hot.” Somnus said, trying not to sound so panicked. He had no idea how the kid had moved so quick.

“Please?”

“No. Play with your toys.”

* * *

 

The second incident was just as harrowing.

Somehow, the little boy had managed to get hold of a marble and went to put it in his mouth. Somnus just managed to prevent him from doing so and was met with a series of cries as Prompto tried to reach for the little object.

Like hell was Somnus returning it to him. Lucky for Somnus, children were easily distracted, and he put on a cartoon and gave him a bottle of milk to sooth Prom’s cries. At least, he could fix that. He could just imagine how angry Ardyn would be if he had to call him because his son had choked on a marble. Somnus would be in the hospital for about 4 months, 3 if Ardyn went easy on him.

* * *

 

The rest of the evening went smoothly.

Somnus texted Ardyn to reassure him and Cor that everything was fine and Prompto was happy. He missed out the parts were Prompto nearly severely burnt himself and nearly choked. It was better for everyone if his brother didn’t know that. After drinking his milk, Prom got sleepy. He cuddled up to Somnus and tried to sleep in his lap. However, Somnus was not allowing his nephew to get into that habit with him. He picked Prompto up and took him to his room. He got him into his pyjamas, changed him and picked a book out to read him a story.

Again, Somnus only turned around for a few seconds and when he looked to where Prompto was sitting, the boy was gone.

Somnus rushed out of the bedroom and saw Prompto running as fast as his little legs would carry him towards the stairs.  Somnus didn’t care that Cor hated it when either Ardyn, he or Regis warped in the house, he did it anyway. He got there just in the nick of time to scoop the child up in his arms before he took a tumble down the stairs. Somnus swore his heart stopped for a moment and moved away from the stairs, in case he tripped and they both fell down them.

Prompto started to giggle and Somnus gave him a very angry look. He didn’t raise his voice, but he spoke in a very harsh tone. “Don’t run close to the stairs. You scared me.”

“Sorry.” Prompto gasped hugging his uncle. He didn’t like it when people got cross. He loved Somnus, he never wanted to get told off by him.

Somnus lightly hugged Prom back, he then went back into the boy’s room and placed him in his cot, so he couldn’t give him a fourth heart attack of the evening. He was not telling either Ardyn or Cor what had happened tonight. He would be skinned alive if he did. At least Prom was safe in his cot and he couldn’t get out.

That’s what Somnus thought...

* * *

 

It was 10:30 when Cor and Ardyn returned.

They both wanted to come back earlier. However, with each update that Ardyn received from Somnus it forced them to remain at the restaurant. Neither of them wanted to be the first to say let's go home, but both of them wanted to get back to their son as quick as they could. Other than, that they had a pleasant night. It was nice to spend some time with just the two of them.

Ardyn parked the car and continued to talk at Cor, who had zoned out on the drive back. He heard a mixture of words like: ‘temple’, ‘time’ and ‘behemoth’. He had no idea what his husband was on about and sometimes it was better than he didn’t. As Ardyn did tend to jump from topic to topic and somehow, from behemoth they were now talking about Somnus.

“Do you know what I have just realised? Prom calls Somnus ‘Om’. If you put an ‘e’ and an ‘n’ on the end you get ‘Omen’. Our darling boy already knows what a prick Somnus is.” Ardyn laughed closing the car door and locking it.

“You need to learn to love your brother.” Cor stated making his way to the front door.

“I do love him. I just really, really, really, really don’t like him and I wouldn’t care if he got shot in the head. To be honest, I would probably laugh.”

“That is the reason why you two don’t get on.”

Ardyn opened the door and called out into the house to make his brother aware of their return. “Somnus, we’re back.”

Neither of them bothered to move from the hallway and waited until Somnus appeared. They heard footsteps making there way to the stairs and when they saw the Founder King he had a face of fury on him. And not surprisingly it was directed at his older brother. Somnus didn’t greet them he just gave them the evils until Cor broke the silence.

“Is everything alright?”

“Don’t know, you tell me?” Somnus growled in a harsh tone. He saw Ardyn didn’t like he had just spoken to Cor in that way, but he didn’t care. He was furious at them.

“Sorry?”

“You both said that Prompto was a healthy normal child. I hate the council as much as you do, but this did need to be addressed.”

Both Cor and Ardyn gave him a weird look and then the realisation hit Ardyn. He took a step back, so he was standing behind Cor, shaking his head and waving his hands to tell Somnus to shut up. But Somnus wasn’t going to listen and turned his attention to the Marshal, ignoring his brother.

Cor exhaled. “Somnus, I have no idea what you are talking about.”

“Ardyn. You really haven’t told your husband?” Somnus said, purposely dropping Ardyn in it.

Cor narrowed his eyes and turned to face Ardyn, who was sheepishly smiling at him. He used a very controlled tone and he did not sound happy at all. “Told me what?”

“Nothing.”

“I put Prom in his cot. I then went to the toilet, and when I opened the bathroom door I found Prompto sitting in the middle of the room. Ardyn, can you please explain how he managed to get out of his cot, and into the bathroom without opening any doors?”

“Ardyn!” Cor tried to stop himself from shouting.

Ardyn raised his hands as if to calm Cor down. He could tell he was furious with him. He didn’t like it when Cor snapped at him. He knew he was in a lot of trouble for keeping that a secret. “Alright, he can teleport. But I didn’t think it was a major issue.”

Somnus shook his head. “I am not even going to bother to try and talk any sense into you. And Cor I won’t say anything. But I think you should tell Regis and Clarus.”

“I will, you don’t need to worry about that.”

“Anyway, other than that, he has been golden.”

“Don’t talk.” Cor raised his hand before Ardyn could say anything. If Somnus had discovered he could teleport, he might as well be aware of everything else Prom could do. Ardyn was not going to stop him either. “You will probably like to know he can also see in the dark.”

“Well, if he was going to have daemon abilities I guess he got the lease dangerous ones.” Somnus shrugged his shoulders.  

“That’s why we didn’t say anything about that one. Anyway, thank you, Somnus. Do you want a drink before you go?”

“No, I’ll show myself out. He’s asleep. Night Cor. Good luck Ardyn.” Somnus patted his brother on the back in sympathy before leaving the house.

They both remained silent for a few seconds after the door closed, to ensure that Somnus was a safe distance away, so he didn’t hear Cor scream at Ardyn. However, the Marshal wasn’t going to do that. Prompto was asleep after all and it wouldn’t be fair to wake him up. But it didn’t stop Cor going right up in Ardyn’s face and speaking harshly at him.

How was this man so stupid! He was 2000 years old, he should know by now when to say things. This was something that Cor should have been aware of.

“You have ten seconds to tell me, why you fucking thought I should be kept in the dark, on our son being able to fucking teleport!”

“I didn’t want to worry you. He’s fine. There is nothing else I swear. I actually thought he had stopped doing it.”

Cor rubbed his face and breathed out. He wished he understood Ardyn’s thought process. “Ardyn… if anyone finds out you, me and Prom are in a shit load of trouble. You should have told me.”

“I know darling. However, there are certain abilities that I no longer possess because I forgot how to use them. I thought the same would happen with Prom.” Ardyn said innocently, trying to make the situation a little better.

“He’s a kid! He’s not going to forget it!” Cor stopped himself before he shouted. There was no point arguing over it. They might as well accept it and deal with the consequences of Ardyn’s actions. “Right. Tomorrow morning, you are going to tell Regis and Clarus about Prompto, this is your mess and I am not cleaning it up.”

“Sorry.”

“You better hope that Somnus isn’t lying and keeps his mouth shut.”

“I’ll kill him if he says anything. And then I’ll kill him again.”

* * *

 

“Hello, my darling nephew.” Ardyn chirped as he walked into Regis’s office without knocking.

The King didn’t look up from what he was reading and sighed. “What have you done now?”

“Why does everyone assume that I have always done something wrong? Can’t I just want a chat with my second favourite nephew of all time.” Regis looked up from his work and stared at him, he was not convinced by that at all. Ardyn let his shoulder’s slumped, Regis was not ever going to believe him. “Okay, I might have lied, about Prompto not possessing any daemonic abilities.”

“For fuck sake Ardyn.” Regis growled hitting his forehead against the palm of his hand.

“He’s still not dangerous, I promise, and Cor only found out last night.”

“I can believe that. Cor would have told me by now. Alright then, what can he do?”

“He can see in the dark that’s all. Gods Ardyn you are making a bigger deal out of this then it needs to be.”

Ardyn glanced over to the left and saw Somnus walking over to them. When did he come in? He hated Somnus so much sometimes, wait… did he just lie to Regis? 

“I take it the only reason why you are telling me, is because he found out about it last night.” Regis concluded keeping his focus on Ardyn.

“No, the real reason is that he doesn’t trust me not to tell you. Well, I have now.”

“Ardyn, I don’t see an issue with this. To be honest, I think that is kind of cool.” Regis smiled. When the King was a child, he wanted to be able to do what Ardyn could. He wanted to be able to see in the dark, teleport, change his appearance to prank people, slow down time, all of it and he was jealous that only Ardyn had the ability. There wasn’t anything to be done with Prom’s abilities, they just had to keep it from the council.

Regis then got confused. Ardyn hadn’t responded to what he had said, he thought he would have at least laughed. “Ardyn?”

“Sorry, I thought I told you not to tell Regis and allow me to do it myself?” Ardyn growled.

“Sorry.”

The King’s concerned turned into annoyance. He clicked his fingers and pointed towards the door. “No. If you two are going to fight, do it out of my office please.”

“Okay. Come on Ardyn.”

The pair left and went to Somnus’s office to have their ‘argument’. And when Ardyn couldn’t hear anyone walking past the room, he narrowed his eyes and questioned his brother carefully.

“Why did you lie?”

With Somnus there was always an alternative motive. He would never do anything nice like that for him. Never. There had to be something up. Somehow, Somnus would gain something in lying. As to what Ardyn couldn’t figure it out. It almost seemed like…

“Because I promised I wouldn’t say anything. And… Prompto is my nephew.”

That was the second thing Ardyn had not expected to hear today. Somnus was keeping to his word for once in his fucking long life. And if Ardyn didn’t dislike Somnus so much he would have been touched at his honesty. It almost seemed like Somnus cared… Nah, not even this little gesture was going to make Ardyn trust him.  

Ardyn sighed. “Cor isn’t going to be happy that I didn’t say anything.”

“Tell him I ordered you not to. Can’t complain then, can he?”

“Guess not.”

Ardyn turned around and opened the door and went to leave but he stopped himself from exiting the room because he knew exactly what Cor would say when he got home if he hadn’t thanked Somnus. Not to mention the fact, that Somnus now had this over him. Ardyn didn’t think that Somnus would ever use the knowledge of his son’s abilities against him, but… he wouldn’t put it past him either.

 He kicked the door and put on the most genuine smile he could muster. This was the best thank you Somnus was going to get. “Oh, and by the way, if you want to babysit again, you are always welcomed too.”

“Thank you Ardyn.” Somnus laughed.

He knew Ardyn didn’t want to say that as he could hear the pain in his voice. But Somnus wasn't going to complain. It was probably the nicest thing he had said to him all year. 


End file.
